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tScuba.com 1 ©SilentScuba 2010 Rev. 1.0 CCR Cave Diving “Almost Simplified” CCR Cave Diving “Almost Simplified” As There Is Nothing Simple About Cave Diving A Complete Guide to Diving a Closed Circuit Rebreather in the Overhead Environment By Dr. Mel Clark
Transcript of - Deep Ideasdeep-ideas.co.uk/images/training_images/ccrcavechapter.pdf · 12 ©SilentScuba 2010...
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CCR Cave Diving “Almost Simplified”
CCR Cave Diving “Almost Simplified”
As There Is NothingSimple About Cave Diving
A Complete Guide to Diving a Closed Circuit Rebreather in the Overhead Environment
By Dr. Mel Clark
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CCR Cave Diving “Almost Simplified”
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Table of Contents
Chapter #1 Introduction • Introduction.........................................
CCR rules............................................• Cave rules............................................• CCR cave rules....................................• Acknowledgements.............................•
Chapter #2 The Cave Diving Environment
Cave Types..........................................• Dissolution..........................................• Coral....................................................• Sea.......................................................• Lava.....................................................• Glacial.................................................• Cave Descriptive Terminology............• Speleotherm.........................................• Vadose cave.........................................• Phreatic cave.......................................• Spring..................................................• Siphon.................................................• Noflow................................................• Sinks....................................................• Sump...................................................• Characteristics of Caves......................• Bottom conditions...............................• Sand.....................................................• Mud.....................................................• Clay.....................................................• Water Make Up...................................• Tannic water........................................• Hydrogensulfide.................................• Haloclines............................................• Water Contamination...........................•
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CCR Cave Diving “Almost Simplified”Chapter #3 CCR Cave Diving Equipment
CCR...................................................• Off-board gas....................................• Harness & BCD................................• Weights.............................................• Bailout and stage cylinders...............• Bailout regulators..............................• Lights................................................• Reels/spools......................................• Markers..............................................• Directional.........................................• Non-directional..................................• Tools..................................................• Maskandfins....................................•
Chapter #4 Cave Diving Hazards Exposed Springs..............................................• Siphons.............................................• Tidalflow..........................................• Noflow.............................................• Restrictions.......................................• Minor.................................................• Moderate...........................................• Major.................................................• Poor visibility....................................• Line traps..........................................• Cave visibility...................................• Haloclines.........................................• Tannicwaterhydrogensulfide..........• Entanglement....................................• Entrapment........................................• Depth.................................................• Distance............................................• Guideline breakage...........................• Equipment failure.............................• Other divers.......................................• Psychological cave hazards.............• Overconfidence................................• Reasons for cave diving fatalities.....• Trained cave diver deaths.................. • Non-trained cave diver deaths...........•
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Chapter #5 Cave Diving Skills Pre-Dive.................................................................• Buildandconfirmation..........................................• SiteevaluationandCCRequipmentconfirmation.• Turn points evaluation and dive plan.....................• In water check and equipment matching................• Communication......................................................• Command signals...................................................• Hand signals............................................................• Number signals.......................................................• Light signals............................................................• Written communication..........................................• Touch communication............................................• Cave navigation......................................................• Mainline.................................................................• Off-shoot line.........................................................• Jump.......................................................................• Gap.........................................................................• T-intersection..........................................................• Primary reel............................................................• Safety reel..............................................................• Jump/gap reel.........................................................• Line trap.................................................................• Tie-off.....................................................................• Placement...............................................................• Cookies or clothes pins..........................................• Two line arrows pointing in the same direction.....• Two line arrows pointing in opposite directions....• Line skills...............................................................• Team positioning....................................................• Making jumps........................................................• Working around lines.............................................• Traverse..................................................................• Circuits...................................................................• Exiting and passing................................................• Swimming..............................................................• Modifiedfrogkick.................................................• Modifiedflutterkick...............................................• Pull and glide.........................................................• Shufflekick............................................................• Cave diving awareness...........................................•
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CCR Cave Diving “Almost Simplified”
Chapter #6 Cave Diving Adverse Situation CaveSpecificAdverseSituation.....................................• Lost line...........................................................................• Broken line......................................................................• Inadvertent jump.............................................................• Loss of navigational awareness.......................................• Blackout situations..........................................................• Lost buddy.......................................................................• Lost light.........................................................................• Line entanglement...........................................................• Entrapment.......................................................................• CCR failure.....................................................................• Loss of buoyancy device.................................................• Sharing air.......................................................................• CCRSpecificAdverseSituations“ABriefOverview”...• Feeling funny...................................................................• Thefirstresponse.............................................................• BO ascent.........................................................................• The three H’s...................................................................• Hyperoxia........................................................................• Hypoxia............................................................................• Hypercapnia.....................................................................• Floods..............................................................................• SCR mode.......................................................................• Off-board gas..................................................................• Open loop........................................................................• Boom...............................................................................• What if game...................................................................• Oxygen cell issues...........................................................• PO2 issues........................................................................• Display issues..................................................................• OC BO supply issues.......................................................• Buddy rescue/recovery....................................................• Omitted decompression...................................................•
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Chapter #7 Cave Dive Planning CaveSpecificDivePlanning...........................• Site deposition.................................................• Dive objectives................................................• Four CCR turn around points..........................• On-board oxygen.............................................• On-board diluent..............................................• Scrubber...........................................................• Bailout gas.......................................................• Stage gas..........................................................• Mixed teams....................................................• CaveNon-specificDivePlanning...................• Oxygen toxicity...............................................• Inert gas loading calculations..........................• Example CCR dive plan mainly one depth.....• Example CCR dive plan mainly two depths....•
Chapter #8 Cave Psychology and Survival Stressors on a dive...........................................• Distance...........................................................• Confinement.....................................................• Physical stress..................................................• Doubting navigation.........................................• Time pressure...................................................• Task loading.....................................................• Highflow.........................................................• Peer pressure....................................................• Ego pressure.....................................................• Dealing with stress...........................................• Recognizing stress in your buddy....................• Choosing your buddy.......................................• Final thoughts..................................................•
References..................................................................
About the author.........................................................
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CCR Cave Diving “Almost Simplified”
Chapter 1: Introduction IntroductionCourse overview
Photo by Curt Bowen
IntroductionCCR rulesCave rulesCCR cave rulesAcknowledgements
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Chapter 2 : The Cave Environment
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Chapter 2: The Cave EnvironmentCave Types Dissolution Coral Sea Lava Glacial Mines and other manmade Cave Descriptive Terminology Speleotherm Vadose cave Phreatic cave Spring Siphon No flow Sinks SumpCharacteristics of Caves Bottom conditions Sand Mud Clay Organic & biological materialWater Make Up Tannic water Hydrogen sulfide HaloclinesHydrogen sulfideHaloclinesWater Contamination
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Chapter 3 : CCR Cave Diving Equipment
Chapter 3: CCR Cave Diving EquipmentCCROff-board gasHarness & BCDWeightsBailout and stage cylindersBailout regulatorsLightsReels/spoolsMarkers Directional Non-directionalToolsMask and fins
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Chapter 4 : Cave Diving Hazards Exposed
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Chapter 4: Cave Diving Hazards ExposedSpringsSiphonsTidal flowNo flowRestrictions Minor Moderate MajorPoor visibilityLine trapsCave visibilityHaloclinesTannic water hydrogen sulfideEntanglementEntrapmentDepthDistanceGuideline breakageEquipment failureOther diversPsychological cave hazardsOver confidence
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Chapter 5 : Cave Diving Skills
Chapter 5: Cave Diving SkillsPre-Dive Build and confirmation Site evaluation and CCR equipment confirmation Turn points evaluation and dive planIn water check and equipment matchingCommunicationCommand signalsHand signalsNumber signalsLight signalsWritten communication
Touch communicationCave navigation Mainline Off-shoot line Jump Gap T-intersection Primary reel Safety reel
Jump/gap reel Line trap Tie-off Placement Cookies or clothes pinsTwo line arrows pointing in the same directionTwo line arrows pointing in opposite directionsLine skillsTeam positioningMaking jumpsWorking around linesTraverseCircuitsExiting and passingSwimming Modified frog kick Modified flutter kick Pull and glide Shuffle kickCave diving awareness
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Chapter 6 : Cave Diving Adverse Situation
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Chapter 6: Cave Diving Adverse SituationCave Specific Adverse Situation Lost line Broken line Inadvertent jump Loss of navigational awareness Blackout situations Lost buddy Lost light Line entanglement Entrapment Loss of buoyancy device Sharing airCCR Specific Adverse Situations “A Brief Overview” Feeling funny The first response BO ascent The three H’s Hyperoxia Hypoxia Hypercapnis Floods SCR mode Off-board gas Open loop BoomWhat if game Oxygen cell issues PO2 issues Display issues OC BO supply issues
Buddy rescue/recoveryOmitted decompression
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Chapter 7 : Cave Dive Planning
Chapter 7: Cave Dive Planning
Cave Specific Dive Planning Site deposition Dive objectives Four CCR turn around points On-board oxygen On-board diluent Scrubber Bailout gasStage gasMixed teamsCave Non-specific Dive Planning Oxygen toxicity Inert gas loading calculations Example CCR dive plan mainly one depth Example CCR dive plan mainly two depths
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Chapter 8 : Cave Psychology and Survival
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Chapter 8:Cave Psychology and SurvivalStressors on a dive Distance Confinement Physical stress Doubting navigation Time pressure Task loading High flow Peer pressure Ego pressureDealing with stressRecognizing stress in your buddyChoosing your buddyFinal thoughts
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Chapter 2 : The Cave EnvironmentOther characteristics the diver needs to understand is the water make up. Tannic water has a reddish color to it. When the tannic level is high this water is next to impossible to see through. Tannis comes from decomposing roots and bark. They also make for incredible photo oppor-tunities. Hydrogen sulfide is a yellowish / brown layer in the water and usually occurs at the interface between fresh andmarinewater layers. For hydrogen sulfide to bemade, the layermustbeanoxicmeaningthereisnooxygenleftinthewater,thenbacteriawhichareanaerobicdegradeplantandanimalsedimentproducingthegashydrogensulfide.Thisgasishighlyflam-mableandquitetoxic.Asadiverpassingthroughahydrogensulfidelayeryouarereallyatlittleriskofthetoxiceffectsasyouarenotbreathingitin.Evenso,Ineverhangaroundtoolonginthislayer.Somediversreportarottenegglikesmell.Also,anybrassyouhavewillturnblackafterbeingexposedtoahydrogensulfidelayer.Inveryhighconcentration,thehydrogensul-fidecanburnyourskin.Ifyousurfaceinahydrogensulfidefilledairspacedonotbreathethegas,stayonyourCCR.Thisisalwayssolidadvicewhenunsureoftheairenvironmentfoundin air pockets in cave systems. Angelita Cenote in Mexico and Hospital Hole sink in the Weeki Wachee river inFlorida, aregood examplesof dive siteswith a hydrogen sulfide layer.Sinkholes near the coast aremost likely to have hydrogen sulfidedue to the saltwater intrusion.
As a diver you need to be most concerned with haloclines. A halocline is the interface between salt and fresh water. The fresh water has a lower density and will sit on top of the more dense salt water layer. There is a distinct interface between the two layers making it look like a mir-ror in some cases. The thickness of the interface can range from inches to feet. This interface when disturbed can completely distort visibility. When you encounter a halocline it is best to swim above or below the interface so you don’t distort the visibility. If this is not possible then swimming in a more side by side manner will allow the following divers to have some visibility. The nice thing about the halocline is it settles relatively quickly and visibility will be restored.
Jo above the hydrogen sulfide layer, Erik below in the hydrogen sulfide layer
Erik working on getting above the hydrogen sulfide layer
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Chapter 3 : CCR Cave Diving Equipment
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MarkersTherearetwomaintypesofmarkers,directional and non-directional. A directional marker points to the direction of the exit. The directional markers are called line arrows. Line arrows are installedonpermanentlinesinthecave,theycanalsobemarkedwiththedistancetothenearestair hole or exit. Divers will also carry at least three line arrows on each dive. All of your line arrows needtobepermanentlymarkedtoidentifytheyareyours.Linearrowsareemployedatjumps,line intersections or end of the line where navigational errors could occur. They take the guessing out of the equation on exiting when used correctly. They can also be used in an emergency such as in a lost line situation. In this case the diver would attach a line arrow to the permanent line pointing in the direction they are exiting when they re-locate the line. This is important since their buddy may stumble along this arrow and now they know one of two things; their buddy is ahead ofthemandissafelyexiting,ortheirbuddyislostandheadinginthewrongdirection,inthiscasethe buddy diver will need to access their turn points and decide to go after them or retreat. Emer-gencyuseoflinemarkerswillbecoveredinChapter6,CaveDivingAdverseSituationSkills.Another use for your line arrows is when you install a jump off a mainline and there is no arrow already there then you must place an arrow on the main line pointing in the exit direction. This arrow will help you know the correct way out and will also serve to hold your jump line in place.
Non-directionalmarkersdonotpoint towardsanexit,they serve to mark points such as maximum penetration distances and help the diver complete circuits. Non-di-rectional markers can also be used to mark the exit side of confusing intersections and permanent line arrows. TheuseofmarkerswillbecoveredinChapter5,CaveDiving Skills. Cookies and clothespins are considered non-directional markers. Each diver should carry at least one non-directional marker but this will depend on the diving location. Mexican caves have many intersections where the diver will require non-directional markers and in this case a minimum of six should be carried.
Josh takes note of the arrows pointing in opposite directions in Peacock Springs, Florida
Josh Places a cookie on the line
Markers attached to a bungee.
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Chapter 5 : Cave Diving Skills
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